Adapter.



J. T. H. DEMPSTER.

ADAPTER.

APPLICATION FILED JUNE 5,1915.

1,172,953. v Patented Feb. 22,1916. Fig. l.

Inventor John T. H. Dempster,

His JTttorneg.

7 UNITED STATES PATENT OFFICE.

JOHN T. H. DEMPSTER, OF SCHENECTAIDY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF'NEW YORK.

ADAPTER.

Application filed June 5, 1915.

To all whom it may concern:

Be it known that 1, JOHN T. H. DEMP- sTER, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Adapters, of which the following is a specification.

My invention relates to adapters for enabling an electric lamp or the like to be operated at its rated or any desired voltage in a socket 0r receptacle between whose terminals some different voltage prevails. It is my aim to combine in a simple, compact, convenient, unitary structure a base or plug device or element for the aforesaid socket; a socket or receptacle for the lamp; and means such as a transformer for producing the desired voltage between the terminals or contacts of said latter socket. I also aim to make the adapter easy and inexpensive to manufacture, and to construct it,as far as possiblefrom standard parts already in use for other purposes. How these and various other advantages can be secured in connection with my invention will be shown by the following description of particular devices embodying it, while the scope of the invention will be indicated by my claims. For convenience, I shall hereinafter distinguish the socket or receptacle which receives the plug or base of the adapter as the main socket, and that which receives the lamp as the adapter socket.

In the accompanying drawing, Figure 1 is a side view of an adapter constructed in accordance with my invention, certain parts being broken away or in section. Fig. 2 is a similar exploded view taken at right angles to Fig. 1, some of the parts in section in Fig. 1 appearing unbroken, and vice versa. Fig. 3 is an end view of one of the exterior parts that appears detached in, Fig. 2, from the right of that figure. Fig. 4 is a similar view of the internal parts exposed in Fig. 2. Fig. 5 is a fragmentary sectional view similar to Fig. 1, showing a modified construction. Fig. 6 is a sectional end view of the device shown in Fig. 5, from the right of a plane corresponding to the line 6-6. Fig. 7 is a view similar to Fig. 5 showing a different modification. Fig. 8 is a view of one of the interior parts shown in Fig. 7 as it would appear' from the right of that figure. Fig. 9 is a view similar to Fig. 5 showing still another modification. Fig. 10

Specification of Letters Patent.

Patented Feb. 22, 1916.

Serial No. 32,330.

is a view of the device shown in Fig. 9 as it appears from the right of that figure.

As the adapter shown in Fig. 1 is intended for use in a main socket or receptacle of the Edison screw type, its base or plug element 10 comprises a screw shell contact or terminal 11 and a center contact or terminal 12 which are united by a body of insulating material 13. Attached at one end to the said base element 10 is a cylindrical casing or shell 14 which contains the transformer 15, and at the other end of said casing is the adapter socket means 16 for holding the base of an incandescent electric lamp. The socket or receptacle 16 is shown as of the bayonet type and as of candelabra or miniature size in comparison with a medium or standard Edison base 10, so that the device may take low voltage miniature tungsten lamps of small candlepower, such as are commonly used on automobiles (six or seven volt two candlepower tail and speedometer lamps, for example,) and is adapted for ordinary household use. With a properly designed transformer and the usual rates for current, such a lamp can be burned all night in one of my adapters for less than half a cent.

Referring to Figs. 1 and 2, it will be seen I that the casing 14 is in two telescoping parts 17 and 18 which may be secured together in any convenient way, as by a solder sweating operation. The outer left-handed part 17 is the ordinary enlarged and insulated skirt of a lamp base structure such as is shown in United States Patent No. 775,689 granted November 22, 1904, to Alfred Swan,this

part 17 being at once mechanically united to,

the terminals 11 and 12 of the base element 10 and electrically separated from them by the insulating material 13,-and differs from the skirt of said patent only in lacking the usual bead intended to give a better hold for the basing cement. The inner right-hand part 18 (see Figs. 1, 2, and 3) has the form of a cup or cap with an opening in its bottom. The socket structure 16 has an enlarged rear portion 20in the cap end of the casing 14 and a reduced front portion 21 that projects through the aforesaid opening in the cap bottom. The cap bottom has engagement means at opposite sides of said opening, the means shown being recesses 22,

22 formed by outward swelling of the metal of the case, and in these recesses are engaged corresponding forward projections 23, 23 from the enlarged part 20 of the socket structure 16, so that the socket structure cannot turn with reference to the casing 14. As shown, the socket structure 16 is like that of United States Patent No. 1,057,025 granted March 25, 1913, to Gilbert lVright, and comprises an outer sheet metal shell with the bayonet slots 24; a flat sided body piece 25 of porcelain, bisque, or other insulating material in the enlarged rear end of said shell; and a pair of springy metal contacts 26, 26 (see Fig. l) secured to said piece and provided with binding screws 27, 27. The piece 25 fits inside a sleeve or liner 28 of fiber or other insulating material and has projections 29, 29 that fit in recesses in the shell. projections 23, 23 above mentioned; this indirect engagement between the piece 25 and the engagement means of the cap bottom prevents the piece 25 from turning and so keeps the contacts 26, 26 in proper angular relation to the bayonet slots 24. The piece 25 is kept in place against the cap end of the casing 1 1: by the transformer 15, as will now be described.

The transformer 15 (of ordinary laminated core construction) is held or clamped in the casing lt between the base and the body piece 25 of the socket structure 16 without any fastening or attachment other than its current connections, and paper is secured over its ends at 31, 31 to increase its friction with adjacent surfaces so that it may be held more firmly and securely, and also to afford protection against chafing and shortcircuiting of the current leads. The primary leads 82, 32 are further protected by being inclosed in rubber tubing, and extend back between the end of the transformer core and the edge of the insulation 13 and are soldered to the screw shell and center contacts 11 and 12 in accordance with the usual practice in basing incandescent lamps. The secondary leads 33, 33 are similarly incased in. .rubber tubing and extend forward to the binding screws 27, 27 of the contacts 26, 26. Additional insulation and resistance to turning or other displacement of the transformer are offered by strips 34, 34 of heavy, stiff insulating fiber or paper which lie between each side of the piece and the adjacent portion of the corresponding contact 26 and extend back beyond the shell of the socket structure 16 at the sides of the transformer core. A wrapping or lining 85 of heavy paper or thin insulating fiber surrounds the transformer 15 and not onlyafiords insulation, but also prevents rattling if the transformer should shift.

Referrin now to Fi 's. 5 and 6 it will be seen that in the device here shown the its bottom, and that this tubular portion 59 has the bayonet slots 6% and takes the place of the reduced front portion 2% of the socket shell of Figs. 1 to 4:- The porcelain body piece that corresponds to the piece 25 is of such diameter as to fit snugly in the front end of the casing within its insulating lining, and the fixed ends of the contacts 66, 66 lie in a shallow groove across its front side. The casing part 58 has engagement means in the form of inward projections 67 that engage in peripheral grooves in the part 65 and prevent the latter from turning. The secondary leads 68 are brought forward to the binding screws of the contacts 66, 66 through other peripheral grooves in the part 65. A ring or washer 69 of fiber or other insulating material is interposed between the part 6-3 and the bottom of the casing part 58.

The construction shown in Figs. 7 and S differs from that of F 5 and 6 in that the porcelain body piece 70 is of a sort of double segment shape and that the contacts 71, T1 are exactly like the contacts 26, 26. The casing part 72 has engagement means in the form of inwardly punched portions 73, 73 of its bottom, and these engage in recesses Ti, H on the front of the piece 70 and prevent the latter from turning. The device illustrated in Figs. 9 and ll) is intended to take miniature lamps with Edison screw bases of candelabra size, and its socket structure 76 is of a type already in commercial use, consisting of a porcelain body piece carrying screw shell and center contacts 77 and 78. Its reduced forward portion 79 that contains the screw shell and center contacts 77 and 78 projects through the opening in the bottom of the casing part 80 and has a flat surface that engages at 81 with a straight portion of the edge of the opening. The enlarged rear portion 82 of the socket structure 76 being smaller than the interior diameter of the cap 80 within its insulating lining, the secondary transformer leads 83 extend forward past its edge to their connection with the contacts 77 and 7 8 by means of binding screws 85 on the front of said enlarged portion. An insulating ring or washer 86 is interposed between the enlargement 82 with the electrical parts and the bottom of the cap 80, and flat nails or pins 87 may, if desired, be driven through the usual screw holes in said enlargement so as to wedge in between the core laminations and secure the socket structure 76 to the transformer 88.

It will be seen that all the devices hereinbefore described present the advantage that the transformer is securely and firmly held or clamped in the casing by the mere assembling and securing or fastening together of the parts, so that any special means for holding or securing it in place would be superfluous. The like applies, also, to the insulating body of the adapter socket, which is securely held or clamped in place between the transformer and the cap end of the casing.

What I claim as new and desire to secure by Letters Patent of the United States,

1. An adapter comprising a base with terminals for engaging those of a socket; a metal casing attached at one end to said base but insulated from its terminals; socket means at the other end of said casing including an insulating body in the casing and terminals carried by said body for engaging those of a lamp base; and a transformer in said casing held between the base end thereof and said body and serving to keep said body in place against the other end of the casing, said transformer having its primary connected to said base terminals and its secondary connected to said socket terminals, but being otherwise unattached to said base.

2. An adapter comprising a base including terminals for engaging those of a standard socket, a metal skirt, and a body of insulating material serving to unite said parts mechanically while separating them electrically; a cap-like metal part telescoping with and secured to said skirt so as to cooperate therewith to form a casing; miniature socket means of the bayonet type at the cap end of said casing including an insulatv ing body in the casing secured so that it cannot turn and terminals carried by said body for engaging those of the miniature lamp base; a transformer in said casing held between said base and said body and serving to keep said body in place, said transformer having its primary connected to the base terminals and its secondary connected to the socket terminals, but being otherwise unat-' tached; and an insulating wrapping about said transformer within the casing.

3. An adapter comprising a base including terminals for engaging those of a standard socket, a metal skirt, and a body of insulating material serving to unite said parts mechanically while separating them electrically; a cap-like metal part telescoping with and secured to said skirt so as to cooperate therewith to form a casing, said part having engagement means in its bottom; socket means of the bayonet type at the cap end of said casing, including an insulating body engaged with said engagement means of the cap bottom and so prevented from turning; terminals carried by said body for engaging a lamp base in said socket means; and a transformer in said casing clamped between said base and said body and serving to keep said body in engagement with the cap bottom, said trans former having its primary connected to the base terminals and its secondary connected to the socket terminals, but being otherwise unattached.

4. An adapter comprising a base with terminals for engaging those of a standard socket; a metal casing attached at one end to said base but insulated from its terminals; miniature socket means at the other end of said casing including an insulating body in the casing and terminals carried thereby for engaging those of a miniature lamp base; and a transformer in said casing having its primary connected to said base terminals and its secondary connected to said socket terminals, and clamped securely in place in, the casing between the base end thereof and the aforesaid insulating body so as to render special means for securing it superfluous.

5. An adapter comprising a base including terminals for engaging those of a standard socket, a metal skirt, and a body of insulating material serving to unite said parts mechanically while separating them electrically; a cap-like metal part telescoping therewith to form a casing; miniature socket means at the cap end of said casing including an insulating body and terminals carried thereby for engaging those of a miniature lamp base; and a transformer in said casing having its primary connected to the base terminals and its secondary connected to the socket terminals, said transformer and said insulating body being securely clamped in place in the casing between the base and cap ends thereof by the securing together of the base and cap parts, so as to render special means for holding them in place superfluous.

In witness whereof, I have hereunto set my hand this 4th day of June, 1915.

JOHN T. H. DEMPSTER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. i 

